1. Field of the Invention
The present invention relates to litter boxes for pets, such as cats. More particularly, the invention comprises a litter box having improved means for retaining odors, misdirected waste and soiled litter within the box and preventing the spread of litter around the box.
2. Description of the Prior Art
Since man first domesticated the cat, it has been common to keep certain of them indoors, almost exclusively. They are easily trained to relieve themselves in a given location, and a box filled with an absorbent, granular material, “litter”, has become an efficient means for containing the cat's waste. Unfortunately, keeping the soiled litter inside the litter box is a problem, since cats tend to scratch and shift the litter to cover the eliminated waste. Likewise, keeping misdirected waste within the confines of the box is important.
U.S. Pat. No. 6,494,165, issued to Russell Asbury on Dec. 17, 2001, discloses an ANIMAL LITTER BOX in which a base member is mated with an upper member encloses one end of the base member, leaving the second end uncovered. A screen grate seals off the enclosed end of the box such that only small particles of uncontaminated litter may pass through the grid of the screen. By prohibiting the animal from entering the enclosed end of the box, its waste is confined to the unenclosed end of the box. The soiled litter may be removed by picking up the box, tipping it so that the clean litter may pass through the screen, leaving the contaminated litter behind to be removed. After removing the contaminated litter, the box may be tipped forward to allow the clean litter to return to the open end of the box. Asbury does not provide a means of confining the litter and misdirected waste to the interior of the box, as does the present invention.
David Schwartz discloses a LITTER BOX ASSEMBLY in U.S. Pat. No. 6,237,534, issued on May 29, 2001. Schwartz presents a fully enclosed box, having a removable lid. Air holes around the upper perimeter of the walls of the box allow air passage into and from the interior of the box. Schwartz contains litter and waste within the box by means of an enclosed passage along one end of the box with an opening through a first wall, and entry into the interior of the box proximate an opposite wall such that an animal must walk the full width of the box before entering the inner chamber. The floor of the passage consists of a grate which allows any litter carried on the animal's feet to drop through into a removable tray below.
A CAT LITTER CONTAINER is disclosed in U.S. Pat. No. 6,205,953, issued to Sharron A. Ginn on Mar. 27, 2001. A base has upstanding sidewals which surround one end and both sides of the base, with a raised ramp area enclosing the second end. The ramp surface has a plurality of grated openings which allow litter from an animal's feet to pass through into a catchment tray beneath the ramp. While Ginn provides a grated ramp to prevent litter from being carried out of the box, it does not prevent litter from being thrown out of the box as the animal scratches or misdirected waste from going over the walls, as does the present invention.
In U.S. Pat. No. 6,065,429, issued on May 23, 2000, Douglas C. Crosse discloses a DISPOSABLE CAT LITTER BOX WASTE RECEPTACLE ASSEMBLY WITH ENCLOSURE in which a disposable, pasteboard base unit holds a standard litter box. A disposable, pasteboard cover unit fits over the litter box, slipping between the litter box and the base unit such that the litter box may be completely enclosed. A removable entryway allows an animal to enter and leave the box. The walls of the cover unit prevent litter and misdirected waste from being thrown from most of the perimeter of the box, but the entryway has no provision for preventing litter from being carried from the box, as does the present invention.
U.S. Pat. No. 5,676,090, issued to Earl W. Cannady, Jr. on Oct. 14, 1997, discloses a SCATTER-RESISTANT LITTER BOX. Cannady presents an enclosed base unit with an opening in one end of the cover unit. A raised ramp below the opening is covered with a carpet like material to trap litter carried on an animal's feet, thereby preventing the litter from being carried from the box. There is no provision for returning litter removed from the animal's feet to the box, as in the present invention, however.
Robert D. Toole, et al., disclose a CAT LITTER BOX in U.S. Pat. No. 5,590,623, issued on Jan. 7, 1997. A lower element is much like a conventional litter box, having a bottom and four generally vertical walls. An upper element, having four inwardly sloping walls and an open top mates with the lower element, thereby increasing the height of the walls of the box. The opening in the top of the upper element is surrounded by a lip which aids in keeping litter from being thrown over the walls as the cat scratches in the litter. Toole, et al., do not provide any means for preventing the animal from carrying litter out of the box, as does the present invention.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.